EP0047364B1 - Use of hardenable resin mixtures for printing inks - Google Patents

Description

The invention relates to the use of curable synthetic resin mixtures for surface coatings and for printing inks for gravure, flexographic and screen printing, consisting of epoxy resin / hardener mixtures and cellulose derivatives.

The surge in demand for packaging materials, particularly in the consumer goods and food industries, especially in recent years, has made changes in packaging techniques necessary. As a result of these changed packaging techniques, practical requirements for the coatings and printing inks used have increased rapidly. The required high temperature resistance for the ever shorter sealing times as well as the resistance to water, acids, bases and especially fats and oils due to tougher food laws are no longer sufficient with the previously used thermoplastic binders.

When using two-component inks based on epoxy resin / hardener systems, the chemical resistance of the coatings has been improved, but the printing speed is not always fast enough in practice. Systems of this type are described in DE-AS 1 494 525. In order to obtain clear solutions, the solvent also had to contain a relatively high proportion of aromatics.

In view of the increasing focus on workplace and environmental protection in recent times, however, practice requires binders for coatings and printing inks, which are readily soluble in aromatic-free solvents. The use of aromatics is also undesirable for technological reasons, since this can cause the rubber and polymer clichés used in flexographic printing to swell.

DE-AS 2 733 597 and DE-OS 2 811 700 describe epoxy resin / hardener mixtures which are clearly soluble in aromatic-free solvents and which also largely meet practical requirements with regard to film properties and chemical resistance. However, improvements are still desirable with regard to the printing speed and the sealing strength of the printing films.

The known prior art also includes printing inks which also use large proportions of cellulose derivatives as binders. To achieve sufficient adhesion to the surface to be printed, however, the use of thermoplastic resins and / or plasticizers as adhesion promoters is necessary. However, these systems cannot achieve a sufficiently high seal resistance and, above all, chemical resistance. Two-component printing inks based on cellulose derivatives and isocyanates give good films in practice, but the use of these systems is not entirely unproblematic, since they are sensitive to moisture on the one hand and the hydroxyl-containing solvents mainly used in this field, in particular the low alcohols such as methanol , Ethanol and isopropanol, cannot be used.

US Pat. No. 2,865,870 describes coating compositions based on epoxy resin / hardener mixtures and cellulose aceto-butyrates. In this system a solution of a solid epoxy resin and a polyaminoamide with an amine hydrogen equivalent weight of 237 is used, which does not give clear films and has to be heat cured.

It was an object of the present invention to find curable binder systems which are readily soluble in aromatics-free solvents and which, after the solvents have evaporated, give rise to physically dry and clear films which cure at room temperature or slightly elevated temperature, which have high seal strengths and on high-speed printing machines can be processed, whereby the coatings or printing films meet the requirements of practice with regard to chemical resistance.

• A) Glycidylverbindungen mit mehr als 1 Epoxidgruppe pro Molekül und Epoxidwerten von 0.35 bis 0,70 und
• B) Celluloseäthern und/oder Celluloseestern in Mengen von 0,5 : 1 bis 5 : 1, bezogen auf das Verhältnis Epoxidharz/Härtermischungen (A + C) : Cellulosederivaten, und
• C) einer oder mehreren Aminverbindungen mit mindestens zwei reaktiven Aminwasserstoffatomen aus der Gruppe der
  • a) aliphatischen Polyamine der allgemeinen Formel
    
    in welcher R ein Alkylrest mit 1-4 Kohlenstoffatomen oder H, R', H oder der Rest -CH₂-CH₂-CN, und x ein Wert von 2-6 sein kann,
  • b) Polyalkylenpolyamine der allgemeinen Formel
    
    in welcher Rein Alkylrest mit 1 -4 Kohtenstoffatomen oder H sein und x die Werte 2-6 und y die Werte 2-4 haben kann,
  • c) Polyätheramine der allgemeinen Formel
    
    in welcher n ein Wert von 3-5, z ein Wert von 0, 1, 2 oder 3 und R¹ ein gegebenenfalls durch einen Alkylrest mit 1 -4 Kohlenstoffatomen substituierter Alkylenrest mit 1 -12 Kohlenstoffatomen sein kann,
  • d) cycloaliphatischen Polyamine der allgemeinen Formel
    
    in welcher R² der Rest
    
    sein kann, mit R³=H oder CH₃-, R⁴=-CH₂― und R⁵ ein Alkylenrest, der gleich oder verschieden und 0,1 oder 2mal vorhanden sein kann und 1 -3 Kohlenstoffatome haben kann,
  • e) Aminoamidverbindungen und/oder imidazolingruppenhaltigen Aminoamidverbindungen mit Aminwasserstoffäquivalentgewichten von 90-175,
  • f) Phenol-Formaldehyd-Amin-Kondensationsprodukte (Mannichbasen) mit mindestens zwei reaktiven Aminwasserstoffatomen,
  • g) Addukte der Aminverbindungen gemäß Ca)-Cf), hergestellt durch Umsetzung von überschüssigem Amin mit Glycidylverbindungen gemäß A)
• D) aromatenfreien Lösungsmitteln und gegebenenfalls
• E) Pigmenten, Farbstoffen, Beschleunigern, reaktiven Verdünnern, Streck- und Verlaufsmitteln.

This object is achieved according to the invention by the use of curable synthetic resin mixtures which, after evaporation of the solvent, give physically dry and clear films and which cure at room temperature or slightly elevated temperature, for printing inks for gravure, flexographic and screen printing, consisting of synthetic resin mixtures as Binder consisting of

• A) Glycidyl compounds with more than 1 epoxy group per molecule and epoxy values from 0.35 to 0.70 and
• B) cellulose ethers and / or cellulose esters in amounts of 0.5: 1 to 5: 1, based on the ratio of epoxy resin / hardener mixtures (A + C): cellulose derivatives, and
• C) one or more amine compounds with at least two reactive amine hydrogen atoms from the group of
  • a) aliphatic polyamines of the general formula
    
    in which R is an alkyl radical with 1-4 carbon atoms or H, R ', H or the radical -CH ₂ -CH ₂ -CN, and x can be a value from 2-6,
  • b) polyalkylene polyamines of the general formula
    
    in which pure alkyl radical with 1 -4 carbon atoms or H and x can have the values 2-6 and y the values 2-4,
  • c) polyether amines of the general formula
    
    in which n can be a value of 3-5, z a value of 0, 1, 2 or 3 and R ^{1 can be} an alkylene radical with 1 -12 carbon atoms optionally substituted by an alkyl radical with 1 -4 carbon atoms,
  • d) cycloaliphatic polyamines of the general formula
    
    in which R ² the rest
    
    with R ³ = H or CH ₃ -, R ⁴ = -CH ₂ - and R ^{5 is} an alkylene radical which may be the same or different and may be present 0.1 or 2 times and may have 1 -3 carbon atoms,
  • e) aminoamide compounds and / or aminoamide compounds containing imidazoline groups with amine hydrogen equivalent weights of 90-175,
  • f) phenol-formaldehyde-amine condensation products (Mannich bases) with at least two reactive amine hydrogen atoms,
  • g) adducts of the amine compounds according to Ca) -Cf), prepared by reacting excess amine with glycidyl compounds according to A)
• D) aromatics-free solvents and optionally
• E) pigments, dyes, accelerators, reactive thinners, extenders and leveling agents.

Another object of the invention is a method for coating or printing on surfaces, which is characterized in that synthetic resin mixtures according to the claims are used as binders.

Another object of the invention is an agent for the method for coating or printing on surfaces, which is characterized in that synthetic resin mixtures according to the claims are used as binders.

The epoxy resins used according to the invention, which can be used both alone and in a mixture, are liquid to semi-solid aromatic glycidyl ethers with more than one epoxy group per molecule which are derived from polyhydric phenols, in particular bisphenols and novolaks, or liquid aliphatic glycidyl ethers which are derived from aliphatic polyhydric alkanols, especially ethylene glycol, propylene glycol, butylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, nonapropylene glycol, tetraethylene glycol, neopentyl glycol, glycerol, pentaerythritol, and their epoxy values are between 0.30 and 0.7, in particular between 0.50 and 0.7, in particular between 0.50 and 0.7.

In addition to the short-chain alkanols mentioned, commercially available higher molecular weight polyalkylene polyether polyols based on, in particular, ethylene glycol and propylene glycol can also be used to elasticize the epoxy resins. The proportion of these alkanols used depends on their molecular weight and the desired degree of elasticity of the epoxy resin.

The cellulose derivatives used in accordance with the invention are commercially available cellulose ethers and cellulose esters which are obtained by reacting cellulose with alkyl halides (ether or low monocarboxylic acids (esters). Depending on the ratio of the reaction components, the cellulose derivatives are obtained with different degrees of substitution.

• Celluloseäther wie Äthylcellulose mit einem Substitutionsgrad von 2,15 bis 2,60, vorwiegend 2,42 bis 2,60,
• Celluloseester wie Celluloseacetat mit einem Substitutionsgrad von 2,2 bis 2,7, Celluloseacetobutyrat mit einem Acetylgehalt von 2 bis 30,5%, einem Butyrylgehalt von 15 bis 54% und einem Hydroxylgruppengehalt von 0,45 bis 4,7%, insbesondere jedoch Celluloseacetopropionat mit einem Acetylgehalt von 1,8 bis 3,6%, einem Propionylgehalt von 40 bis 46,5% und einem Hydroxylgruppengehalt von 1,6 bis 5,5%.

Products which are soluble in low-boiling organic solvents, such as in particular, are preferred according to the invention

• Cellulose ethers such as ethyl cellulose with a degree of substitution from 2.15 to 2.60, predominantly 2.42 up to 2.60.
• Cellulose esters such as cellulose acetate with a degree of substitution of 2.2 to 2.7, cellulose acetobutyrate with an acetyl content of 2 to 30.5%, a butyryl content of 15 to 54% and a hydroxyl group content of 0.45 to 4.7%, but especially cellulose acetopropionate with an acetyl content of 1.8 to 3.6%, a propionyl content of 40 to 46.5% and a hydroxyl group content of 1.6 to 5.5%.

In the preferred use according to the invention, these cellulose derivatives are used in printing ink binders in amounts of epoxy resin / hardener mixtures (A + C): cellulose derivatives (R) of approximately 0.5: 1 to 5: 1, in particular 1: 1 to 3; 1, also used.

High proportions of cellulose derivatives have a favorable effect in the direction of fast-drying, tack-free surfaces, as are absolutely necessary for high-speed printing presses when printing from roll to roll. Excessively high proportions, however, impair the adhesion of the film to the surface.

The amount of cellulose derivatives used is limited in printing inks when printing from roll to roll due to the required printing speed, while the area is less critical in the screen printing process.

When it is also possible to use paints according to the invention, which are applied by machine or manually, spontaneous freedom from surface stickiness is not always necessary or desirable, so that the proportion of cellulose derivatives can be adapted to practical requirements, i. that is, proportions from 10: 1 to 15: 1 are quite practical.

While ethyl cellulose and cellulose acetate are not compatible with other cellulose derivatives, cellulose acetobutyrate and cellulose acetopropionate can also be mixed with one another.

• Äthylendiamin, Propylendiamin, Hexamethylendiamin, Trimethylhexamethylendiamin,
• sowie die N und N,N'-Cyanäthylierungsprodukte dieser Diamine;
• Diäthylentriamin, Dipropylentriamin, Triäthylentetramin, Tetraäthylenpentamin,
• 3-(2-Aminoäthyl)-Aminopropylamin, Bis(3-Aminopropyl)-Äthylendiamin;
• 1,7-Diamino-4-oxa-heptan, 1,7-Diamino-3,5-dioxa-heptan, 1,10-Diamino-4,7-dioxa-decan,
• 1,10-Diamino-4,7-dioxa-5-methyldecan, 1,11-Diamino-6-oxa-undecan,
• 1,11-Diamino-4,8-dioxaundecan, 1,11-Diamino-4,8-dioxa-5-methyl-undecan,
• 1,11-Diamino-4,8-dioxa-5,6-dimethyl-7-propionyl-undecan,
• 1,12-Diamino-4,9-dioxa-dodecan, 1,13-Diamino-4,10-dioxa-tridecan,
• 1,13-Diamino-4,7,10-trioxa-5,8-dimethyl-tridecan, 1,14-Diamino-4,11-dioxa-tetradecan,
• 1,14-Diamino-4,7,10-trioxatetradecan, 1,16-Diamino-4,7,10,13-tetraoxa-hexadecan,
• 1,20-Diamino-4,17-dioxa-eicosan;
• 1-Amino-4(γ-aminopropyl)cyclohexan, 3-Aminomethyl-3,5,5-trimethyl-cyclohexylamin,
• 4,4'-Diaminodicyclohexyl-methan, 3,3'-Dimethyl-4,4'-diaminodicyclohexyl-methan,
• Bis-(aminomethyl)cyclohexan, 1,4-Diamino-cyclohexan;
• Polyamide und imidazolingruppenhaltige Polyaminoamide auf Basis mono- und polymerer Fettsäure und überschüssigen Aminen mit Aminwasserstoffäquivalentgewichten von 90―175.

The amine compounds used as curing agents according to the invention are

• Ethylenediamine, propylenediamine, hexamethylenediamine, trimethylhexamethylenediamine,
• as well as the N and N, N'-cyanoethylation products of these diamines;
• Diethylenetriamine, dipropylenetriamine, triethylenetetramine, tetraethylenepentamine,
• 3- (2-aminoethyl) aminopropylamine, bis (3-aminopropyl) ethylenediamine;
• 1,7-diamino-4-oxa-heptane, 1,7-diamino-3,5-dioxa-heptane, 1,10-diamino-4,7-dioxa-decane,
• 1,10-diamino-4,7-dioxa-5-methyldecane, 1,11-diamino-6-oxa-undecane,
• 1,11-diamino-4,8-dioxaundecane, 1,11-diamino-4,8-dioxa-5-methyl-undecane,
• 1,11-diamino-4,8-dioxa-5,6-dimethyl-7-propionyl-undecane,
• 1,12-diamino-4,9-dioxa-dodecane, 1,13-diamino-4,10-dioxa-tridecane,
• 1,13-diamino-4,7,10-trioxa-5,8-dimethyl-tridecane, 1,14-diamino-4,11-dioxa-tetradecane,
• 1,14-diamino-4,7,10-trioxatetradecane, 1,16-diamino-4,7,10,13-tetraoxa-hexadecane,
• 1,20-diamino-4,17-dioxa-eicosan;
• 1-amino-4 (γ-aminopropyl) cyclohexane, 3-aminomethyl-3,5,5-trimethyl-cyclohexylamine,
• 4,4'-diaminodicyclohexyl methane, 3,3'-dimethyl-4,4'-diaminodicyclohexyl methane,
• Bis (aminomethyl) cyclohexane, 1,4-diamino-cyclohexane;
• Polyamides and polyaminoamides containing imidazoline groups based on mono- and polymeric fatty acids and excess amines with amine hydrogen equivalent weights of 90―175.

Aminoamides and aminoamides containing imidazoline groups are the compounds which belong to the prior art and are used in practice as curing agents for epoxy compounds, as described, for example, in German Patent Specifications 972 757.1 074 856, German Patent Specifications 1 041 246, 1 089 544, 1 106 495, 1 295 869, 1 250 918, British patents 803 517, 810 248, 873 224, 865656, 956 709, Belgian patent 593299, French patent 1 264 244, and US patents 2 705 223, 2 712 001, 2881 194, 2 966 478, 3002941, 3 062 773 and 3 188 566 are suitable.

• e1) Monocarbonsäuren, wie geradkettigen oder verzweigten Alkylcarbonsäuren mit 16 bis 22, bevorzugt mit 18 C-Atomen, wie insbesondere die natürlichen Fettsäuren wie Palmitin-, Stearin-, Öl-, Linol-, Linolen-, Tallölfettsäure oder
• e2) die durch Polymerisation von ungesättigten natürlichen und synthetischen einbasischen aliphatischen Fettsäuren mit 16-22 Kohlenstoffatomen, bevorzugt 18 Kohlenstofatomen, nach bekannten Methoden erhältlichen sogenannten dimeren Fettsäuren (vgl. z. B. DE-OS 1 443938, DE-OS 1 443968, DE-PS 2 118 702 und DE-AS 1 280 852). Typische im Handel erhältliche polymerisierte Fettsäuren haben etwa folgende Zusammensetzung:
  
  Es können jedoch auch Fettsäuren verwendet werden, deren trimerer und höherfunktioneller Gehalt oder deren Dimeranteil durch geeignete Destillationsverfahren angereichert worden ist oder Fettsäuren, die nach bekannten Verfahren hydriert worden sind oder
• e3) aus ungesättigten höheren Fettsäuren mit 16 -22, insbesondere 18 Kohlenstoffatomen oder deren Ester mit aromatischen Vinylverbindungen den durch Copolymerisation erhaltenen Carbonsäuren (z. B. GB-PS 803 517) oder die Additionsprodukte von Acrylsäure an höhere monomere Fettsäuren mit 16-22 C-Atomen, die durch Carboxylierung von ungesättigten monomeren Fettsäuren mit 16 - 22 C-Atomen erhaltenen Dicarbonsäuren oder
• e4) Säuren, hergestellt durch Addition von Phenol bzw. dessen Substitutionsprodukten an ungesättigte Monocarbonsäuren wie Hydroxyphenylstearinsäure (z. B. DE-OS 1 543 754) oder 2,2-Bis-(hydroxyphenyl)-valeriansäure oder Additionsprodukte von Phenol an Polycarbonsäuren, wie dimere Fettsäure (z. B. US-PS 3 468 920)

mit Polyaminen im Verhältnis von Amingruppen zu Carboxylgruppen von > 1.Aminoamides and aminoamides containing imidazoline groups, which are prepared by reacting

• e1) monocarboxylic acids, such as straight-chain or branched alkylcarboxylic acids having 16 to 22, preferably having 18 carbon atoms, such as, in particular, the natural fatty acids such as palmitic, stearic, oleic, linoleic, linolenic, tall oil fatty acid or
• e2) the so-called dimeric fatty acids obtainable by polymerization of unsaturated natural and synthetic monobasic aliphatic fatty acids with 16-22 carbon atoms, preferably 18 carbon atoms, by known methods (cf., for example, DE-OS 1 443938, DE-OS 1 443968, DE -PS 2 118 702 and DE-AS 1 280 852). Typical commercially available polymerized fatty acids have the following composition:
  
  However, it is also possible to use fatty acids whose trimer and higher functional content or whose dimer content has been enriched by suitable distillation processes or fatty acids which have been hydrogenated by known processes or
• e3) from unsaturated higher fatty acids with 16-22, in particular 18 carbon atoms or their esters with aromatic vinyl compounds, the carboxylic acids obtained by copolymerization (for example GB-PS 803 517) or the addition products of acrylic acid with higher monomeric fatty acids with 16-22 ° C. -Atoms, the dicarboxylic acids or obtained by carboxylation of unsaturated monomeric fatty acids with 16-22 carbon atoms
• e4) acids produced by adding phenol or its substitution products to unsaturated monocarboxylic acids such as hydroxyphenylstearic acid (for example DE-OS 1 543 754) or 2,2-bis (hydroxyphenyl) valeric acid or addition products of phenol to polycarboxylic acids, such as dimeric fatty acid (e.g. U.S. Patent 3,468,920)

with polyamines in the ratio of amine groups to carboxyl groups of> 1.

In general, the acids of the above groups are used for the condensation with the polyamines, but mixtures can also be used. The polyaminoamides and polyaminoimidazolines of the monomeric or polymeric fatty acids mentioned under e1) and e2) have acquired particular importance in technology and are therefore preferably used according to the invention.

• e5) Polyalkylenpolyamine der allgemeinen Formel wie Polyäthylenpolyamine, wie Diäthylentriamin, Triäthylentetramin, Tetraäthylenpentamin oder Polypropylenpolyamin, sowie die durch Cyanäthylierung von Polyaminen, insbesondere des Äthylendiamins und anschließende Hydrierung erhaltenen Polyamine (Firmenprospekt der BASF AG, 1976) oder
• e6) gegebenenfalls substituierte Alkylenpolyamine der allgemeinen Formel I wie Äthylendiamin, Propylendiamine, Butylendiamine, Hexylendiamine

oder Mischungen von zwei oder mehreren der unter e5) und e6) genannten Amine eingesetzt. Erfindungsgemäß bevorzugt werden die unter e5) genannten Polyamine eingesetzt.The amine components used according to the invention for the production of the polyaminoamides are polyamines such as

• e5) polyalkylene polyamines of the general formula such as polyethylene polyamines, such as diethylene triamine, triethylene tetramine, tetraethylene pentamine or polypropylene polyamine, and the polyamines obtained by cyanoethylation of polyamines, in particular ethylene diamine and subsequent hydrogenation (company brochure from BASF AG, 1976) or
• e6) optionally substituted alkylene polyamines of the general formula I such as ethylenediamine, propylenediamines, butylenediamines, hexylenediamines

or mixtures of two or more of the amines mentioned under e5) and e6). According to the invention, the polyamines mentioned under e5) are preferably used.

Preferred aminoamides or aminoamides containing imidazoline groups according to the invention have amine hydrogen equivalent weights of 90 to 175.

Mannich bases in the sense of the above invention are reaction products of phenols, formaldehyde and polyvalent amines. The phenols which can be used are monophenols, such as phenol, ortho-, metha-, para-cresol, the isomeric xylenols, para-tertiary-butylphenol, para-nonylphenol, _A- naphthol, 8-naphthol, and also di- and polyphenols, such as resorcinol, Hydroquinone, 4,4'-dioxydiphenyl, 4,4'-dioxydiphenyl ether, 4,4'-dioxydiphenylsulfone, 4,4'-dioxydiphenylmethane, bisphenol A, and the condensation products called phenol and formaldehyde called novolaks.

The polyamines mentioned under Ca) and Cb) can be used as polyvalent amines, but in particular hexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, triethylenetetramine and xylylenediamine or mixtures of these amines. The Mannich bases prepared by amine exchange, which are described in DE-OS 2 805 853, are also suitable.

The amine compounds mentioned under Ca) to Cf) can be pre-adducted with some of the epoxy resins required for complete curing. For this purpose, the low-viscosity aliphatic and aromatic glycidyl ethers such as neopentyl glycol diglycidyl ether and / or bisphenol A or F diglycidyl ether are preferably used. The degree of adducting is determined by the amine and epoxy resin components used in each case and is controlled so that the overall mixtures result in clear films.

The amine components mentioned according to C) can be used either alone or mixed with one another or with one another.

The use of alcoholic, phenolic and aminic accelerators customary in this field is preferred according to the invention when using the curing agents according to Ca) to Cd) and Cg) to achieve rapid curing at room temperature. Such connections are e.g. B. benzyl alcohol, furfuryl alcohol, nonylphenol, para-tertiary-butylphenol, dimethylaminomethylphenol and tris (dimethylaminomethyl) phenol.

If necessary, the reactive diluents customary in this field, such as cresyl glycidyl ether, p-tert-butylphenyl glycidyl ether, phenyl glycidyl ether, alkyl hexyl glycidyl ether, can also be used.

For the mixtures used according to the invention, the solvents are also selected taking into account the printing process used.

Fast printing evaporating solvents such as mixtures of low aliphatic alcohols with 1-4 carbon atoms, esters such as ethyl, propyl, isopropyl, butyl, isobutyl esters, ketones such as Ace are used for printing processes with high printing speeds (rotary printing) clay, methyl ethyl ketone, methyl isobutyl ketone, methyl n-butyl ketone used.

For printing processes with low printing speeds, such as. B. screen printing process or for surface coatings, solvents with relatively long evaporation times such as the glycol ethers and acetates customary in this field, optionally in a mixture with other solvents suitable for the respective printing process, can be used.

With the method according to the invention, inorganic and organic substrates can be printed or coated. There are the usual films in the printing industry from z. B. polyamides, polyesters or polyester amides, heat-sensitive films made of z. As polyethylene and polypropylene, co-extrusion films made of polyethylene and polypropylene, untreated or coated with polymers or coated with nitrocellulose cellophane films, paper, cardboard and optionally polyvinyl chloride or its copolymers, and metal foils such as. B. aluminum foils. Combinations of these materials may also be possible. The coatings can on the usual materials in the construction sector such. B. on concrete, metal, wood, plastics.

Preparation of the formulations 1. Epoxy resin formulations

• a) In a mixture consisting of 10.0 g of ethanol, 27.2 g of ethyl acetate and 37.0 g of acetone, 15.0 g of novolak epoxy resin (epoxy value = 0.56) and 10.8 g of cellulose acetopropionate are stirred and lighter Warming solved.
  After cooling, the solution is ready for use (Example 16, Table 3).
• b) In a mixture consisting of 50.0 g of ethyl acetate and 10.0 g of methyl ethyl ketone, 10.5 g of novolak epoxy resin (epoxy value 0.56), 10.5 g of bisphenol A epoxy resin (epoxy value 0.52) are 14.0 g of cellulose propionate and 5.0 g of ketone resin dissolved with stirring and gentle heating. After cooling, a ready-to-use formulation is obtained which has a very slight turbidity but has no effect on the printing film gloss obtained later (Example 28, Table 3).

2. Hardener formulations

• a) In a mixture consisting of 7.0 g of ethanol, 6.0 g of ethyl acetate and 5.5 g of acetone, 2.7 g of dipropylenetriamine are dissolved by stirring and then 3.8 g of bisphenol A epoxy resin (epoxy value 0.52 ) added. After heating for 3 hours at 40-50 ° C., the mixture is cooled to room temperature; the hardener solution is then ready for use (Example 16, Table 4).
• b) 7.9 g of hardener No. 13 (Table 2) are dissolved in 17.1 g of ethanol by stirring; the solution is immediately ready for use (Example 28, Table 4).

Ready-to-use formulations in the correct mixing ratio are obtained if 25 g of the solutions according to 2a) or 1b) are added to 100 g of the solutions according to 1a) or 1b) and mixed well (Examples 16 and 28, Table 5).

All resin and hardener formulations listed in Tables 3 and 4 and the mixtures listed in Table 5 are prepared in the same way.

Production of printing inks

After completion, the epoxy resin solutions are pigmented with the dispersing equipment common in the printing ink industry. Organic and inorganic pigments and soluble dyes can be used for this in the amounts customary in this field. After the hardener and epoxy resin components have been mixed in the correct mixing ratio (see Table V), the finished printing inks are diluted to the correct printing viscosity, depending on the requirements of the respective printing process.

A selection of the printing inks produced in this way was printed with a commercial printing machine from roll to roll on polyethylene and aluminum foil. The prints were physically dry immediately after the solvents had evaporated, so that no sticking or clapping of the colors on the back of the rolled-up film was observed. After a standing time of 7 days at room temperature, the prints were subjected to a detailed test that is common in the printing ink industry. The values for the mechanical, chemical and thermal resistance properties are listed in Tables VI and VII.

Description of the test methods used 1. Adhesive strength

The adhesive strength of print films on a print carrier is tested with Tesafilm ^@ strips. 10 strips are stuck on quickly or slowly.

2. Scratch resistance

The print films are more or less scratched with the fingernail.

3. Chemical resistance

After storage in the respective chemicals for 24 hours, the mechanical properties such as adhesion, scratch and abrasion resistance of the print films are checked immediately after removal from the test medium and after a 10-minute recovery period in air and evaluated accordingly.

4. Seal strength

• Bewertung der Testmethoden 1 -3
  
• Bewertung der Testmethode 4
  

Approx. 4 cm wide strips of prints on aluminum foil are folded pressure against pressure and sealed against each other in a Brugger automatic sealer under a load of 1 kg / _M ² pressure and 1 sec sealing time with increasing temperatures of 80-250 ° C. After cooling, it is unfolded and assessed.

• Evaluation of test methods 1 -3
  
• Evaluation of the test method 4
  

As the values determined show, when using the synthetic resin mixtures according to the invention as printing ink binders, very good chemical resistance and, above all, significantly higher heat resistance (sealing strength) were obtained than with the previously known two-component printing inks based on epoxy resin.

Claims (10)

1. Use of hardenable synthetic resin mixtures, which after evaporation of the solvent result in physically dry and clear films and harden at room temperature or slightly increased temperature, as binders for printing inks for gravure, flexographic and screen printing, characterised in that the synthetic resin mixtures comprise:

A) glycidyl compounds having more than one epoxide group per molecule and epoxide values of 0.35 to 0.70, and

B) cellulose ethers and/or cellulose esters in volumes corresponding to a ratio 0.5 : 1 to 5 : 1, being the ratio of epoxide resin/hardener mixtures (A + C): cellulose derivatives, and

C) one or more amine compounds with at least two reactive amine hydrogen atoms selected from the group of

a) aliphatic polyamines of the general formula:

where R is an alkyl residue with 1 -4 carbon atoms or H, R' is H or the residue -CH₂-CH₂-CN, and x has a value of 2-6,

b) polyalkylenepolyamines of the general formula:

where R is an alkyl residue with 1 -4 carbon atoms or H, and x has a value of 2 - 6 and y a value of 2-4,

c) polyetheramines of the general formula:

where n has a value of 3-5, z a value of 0, 1, 2 or 3, and R¹ is an alkylene residue with 1 -12 carbon atoms, optionally substituted by an alkyl residue with 1 -4 carbon atoms,

d) cycloaliphatic polyamines of the general formula:

where R² is the residue:

where R³=H or CH₃-, R⁴=-CH₂- and R⁵ = an alkylene residue which may be the same or different and be present 0, 1 or 2 times and may have 1 - 3 carbon atoms,

e) aminoamide compounds and/or aminoamide compounds containing imidazoline groups with amine-hydrogen equivalent weights of 90-175,

f) phenol-formaldehyde-amine condensation products (Mannich bases) with at least two reactive amino-hydrogen atoms,

g) adducts of the amine compounds in accordance with Ca)-Cf) produced by a reaction of excess amine with glycidyl compounds in accordance with (A).

D) solvents free of aromatic compounds and, optionally

E) pigments, dyes, accelerators, reactive thinners, extenders and levelling agents.

2. Use of the hardenable synthetic resin mixtures in accordance with claim 1, characterised in that the glycidyl compounds used in accordance with A) are glycidyl ethers based on novolaks with epoxide values of 0.50 - 0.60.

3. Use of hardenable synthetic resin mixtures according to claim 1, characterised in that the amino compounds used in accordance with C) are monocyanoethylated trimethylhexamethylenediamine, dipropylenetriamine, 1,12-diamino-4,1-dioxa-dodecane, isophorone-diamine, aminoamine based on a C₁₈-monocarboxylic acid and tetraethylene-pentamine, aminoamide based on dimerized fatty acid and triethylenetetramine or Mannich bases based on phenol, formaldehyde and trimethylhexamethylenediamine or p-tert-butylphenol, formaldehyde and trimethylhexamethylenediamine and xylylenediamine.

4. Use of hardenable synthetic resin mixtures in accordance with claim 1, characterised in that the resin hardener mixtures used arc mixtures of

A) novolakglycidylether with an epoxide value of 0.55-0.57 and

B) cellulose acetopropionate in volumes of 1 : 1 to 1 : 3 relative to the epoxide/hardener volume and

C) an adduct consisting of neopentylglycolglycidylether and dipropylenetriamine with an amine-hydrogen equivalent weight of 71.

5. Use of resin-hardener mixtures in accordance with claim 4, characterised in that the hardener in accordance with C) is a mixture consisting of dipropylenetriamine (amine-hydrogen equivalent weight 28) and the Mannich base of p-tert-butylphenol, formaldehyde and trimethylhexamethylenediamine and xylylenediamine.

6. Use of resin-hardener mixtures in accordance with claim 4, characterised in that the hardener used is a mixture of an adduct of isohoronediamine and bisphenol-A-diglycidylether (epoxide value 0.52) with benzylalcohol and nonylphenol as accelerator with an amine-hydrogen equivalent weight of the mixture of 111 and the Mannich base of p-tert-butylphenol, formaldehyde and trimethylhexameth ylenediamine and xylylenediamine.

7. Use of resin-hardener mixtures in accordance with claim 4, characterised in that a mixture of an adduct of isophoronediamine and bisphenol-A-diglycidylether (epoxide value 0.52) with benzyl alcohol and nonylphenol as accelerator and an amine-hydrogen equivalent weight of the mixture of 111 and dipropylenetriamine is used.

8. Use or resin-hardener mixtures in accordance with the claims 1 to 7, characterised in that the cellulose component used in accordance with B) is cellulose acetoproprionate.

9. Method for printing surfaces, characterised in that the binders used are synthetic resin mixtures in accordance with claims 1 -8.

10. Product for use in printing surfaces, characterised in that the binders used are synthetic resin mixtures in accordance with claims 1-8.